A couple of recent studies have added to the increasing evidence that anthropogenic ocean noise can have deleterious effects on fish. As the years go by, it’s becoming clear that it’s not just whales and dolphins that are struggling with human noise in the sea.

A lab-based study of European sea bass found that recordings of pile driving sounds (often associated with bridge, port, or wind farm construction) and of drilling sounds triggered subtle yet troubling changes in behavior. The sudden bursts of pile driving induced a startle response, while both kinds of sounds increased stress, as measured by the fishes’ respiration rate. In addition, both sources of human noise appeared to suppress their normal predator inspection behavior, which could make them more susceptible to predation (though after a half hour of drilling noise, the bass returned to normal anti-predator behavior).

Ilaria Spiga, a doctoral candidate at Newcastle University and the lead author of the study, explained, “Exposure to underwater noises can make it harder for fishes to detect and react to predators. . . If fishes actively avoid areas where these sounds are present it could prevent them from entering spawning grounds, or affect communication between individuals.”

The question of communication was at the heart of a new study from the same team that has been investigating how shipping noise can reduce the communication space of whales. The new research, led by Jenni Stanley, focuses on two key commercial fish, cod and haddock. Utilizing the network of bottom-mounted hydrophones that they’ve deployed in Massachusetts Bay for the past decade, the researchers recorded the grunts of cod and the “knocks” of haddock, along with the noise of ships in the area. The most striking effect was the difference in noise levels between the cod’s winter spawning site near the Boston shipping lanes and their spring spawning site near the fishing fleets of Cape Ann, north of Boston. While there were many more boats near the spring site, these smaller vessels resulted in overall sound levels 11-15dB lower than at the winter site, which in turn allowed the cod to maintain dramatically larger communication space. (The distances over which cod could be heard were not measured directly, but rather calculated based on the source levels of their grunts and the prevailing levels of ship noise.)

At the quieter spring sites, the mean communication distance was 15 meters (below 11m during the noisiest 10% of the time, and over 19m at the quietest 10% of times), while in the winter sites, they could only be heard out to 2.7 meters (with 10% extremes of under 2.1m and over 3.4m at the very best of times). The haddock spawning sites had intermediate noise levels, and at their loudest could be heard at slightly longer range than the winter cod, though a weaker form of their call had the shortest range of any of those assessed.

Mounting evidence suggests that acoustic communication can affect the survival and reproductive success of fishes, including direct evidence for Atlantic cod. . . .Unlike haddock who have a wide acoustic repertoire, Atlantic cod are thought to be less versatile vocalists during courtship. . . If anthropogenic sound reduces the efficiency of the vocalizations utilized by these species, this interference could potentially impact their reproductive success and survival through the incorrect assessment of the quality of potential mates or competitors, reduction in the ability to attract mates and/or the mistiming of gamete release.

While stressing that we still have much to learn about how fish may compensate for noise (by using other cues to find each other, vocalizing during quieter moments, increasing the intensity of their sounds, etc.), the authors conclude:

This research highlights the need to gain a better understanding of the spatial and temporal use of unique habitats that are predictably used for critical life history events in declining populations. Identifying and better understanding these consequences [at all levels of the food chain] is important to advancing the management of shared acoustic space.

Last fall’s innovative 2-month voluntary slow-down of ships traveling to and from the Port of Vancouver was successful on one count—average overall shipping noise was reduced by 44%—but a stark absence of the normally abundant resident orcas stymied the equally important second line of inquiry: how would reducing the noise level, but spreading more moderate noise over longer time periods, affect orca behavior?

About 60 percent of the ships transiting Haro Strait complied with the voluntary speed restrictions; even this level of participation succeeded in reducing the overall level of ship noise by 2.5 decibels, very close to the 3dB target set by the International Whaling Commission a decade ago. Thanks to the logarithmic scale of decibel measurements, a 3dB reduction amounts to cutting the sound energy in half. This is great news, a real-world confirmation that the noise of global shipping can be reduced relatively easily—albeit by increasing transit time.

It’s this element that marine mammal experts remain uncertain about. Slower ships remain audible for longer during their passage, though at a lower volume; perhaps worse, the quiet periods between the passage of large ships became notably shorter and noisier, thanks to the lingering presence of ships in the mid-distance. What is more livable: a constant lower noise level or trading off louder periods for interims with relatively little noise? As researcher Scott Veirs notes. “I’m not sure which I would prefer, but we definitely don’t know which the whales prefer.”

An excellent in-depth article on the Seattle nonprofit news site Crosscut tells the tale of the researchers waiting on shore to monitor whale behavior. But rather than seeing whales on most days, there were no orcas at all during the first month of the slowdown, and only six appearances in the second month. A stark lack of salmon kept the orcas out of the area; salmon shortages are the primary factor driving the decline in the Southern Resident orca population. A recent modeling study by a diverse group of researchers suggested that increasing salmon numbers by 15% while also reducing shipping noise by half would allow the resident population to recover. (The decrease in salmon numbers is compounded by a boom in populations of seals and sea lions, who also eat salmon.)

Piloting his 31-foot research boat Wishart back to Seattle from the San Juan Island study site, Rob Williams mused on his 20 years studying killer whales. “A whole lot of science has been done already,” he said. It may be time to start making some difficult policy decisions about vessel noise, Williams said, and that means weighing safety issues and economic tradeoffs alongside concern for the whales. A number of factors, including the Canadian government’s approval of Kinder Morgan’s pipeline to export oil to Asia, could drive future increases in Port of Vancouver vessel traffic.

“What we have to do next is to have some really uncomfortable conversations. . .about how much of this acoustic space do we think it is fair to ask the whales to give up.” Williams said. “And how much are we willing to give up to have killer whales persist?”

A recent line of research ups the ante on how widespread the impacts of human noise in the ocean may be. Oysters appear to suddenly and dramatically close up in response to low frequency noise at intensities that are relatively common—beginning at sound as levels as low as 120dB, and ramping up rapidly above 140dB. The figure at left shows how fast the shells closed at top and the degree of closing at bottom (from the minimal to maximal responses observed). Effects were strongest from 10-200Hz, a frequency range that includes shipping and seismic survey sounds.

While oysters, like many other shellfish and crustaceans, do not have ears, they are sensitive to vibrations; earlier oyster studies speculate that they may be responding to subtle seabed vibrations, though it’s also possible their tissues are responding to water-borne particle motion. Another recent paper looked at scallop behavior and mortality after exposure to airguns, and reports that negative effects were seen for months after exposure:

“Exposure to seismic signals was found to significantly increase mortality, particularly over a chronic (months postexposure) time scale, though not beyond naturally occurring rates of mortality. Exposure did not elicit energetically expensive behaviors, but scallops showed significant changes in behavioral patterns during exposure, through a reduction in classic behaviors and demonstration of a nonclassic “flinch” response to air gun signals. … Hemolymph (blood analog) physiology showed a compromised capacity for homeostasis and potential immunodeficiency, … with effects observed over acute (hours to days) and chronic (months) scales. … Given the scope of physiological disruption, we conclude that seismic exposure can harm scallops.”

As our colleagues at Ocean Conservation stress in their coverage of these new developments, all this is part of a rapidly expanding awareness of the ways that our noise compromises ocean life far beyond the whales and dolphins that were the focus of initial concern and research. Early this year saw the publication of a comprehensive review of the potential impacts of marine seismic surveys on fish & invertebrates. The authors point out that on many topics (fish catch rates, startle responses, tissue damage) results have been mixed/contradictory, with some studies finding negative impacts and others finding no response; their paper lays out key areas for future research that could begin to clarify these ambiguities.

Tim Leighton, Professor of Ultrasonics and Underwater Acoustics and study co-author, said: “There has been much discussion over the last decade of the extent to which whales, dolphins and fish stocks, might be disturbed by the sounds from shipping, windfarms and their construction, seismic exploration etc. However, one set of ocean denizens has until now been ignored, and unlike these other classes, they cannot easily move away from loud man-made sound sources. These are the bottom feeders, such as crabs, shellfish and invertebrates similar to the ones in our study, which are crucial to healthy and commercially successful oceans because they form the bottom of the food chain.” Co-author Dr Chris Hauton, Associate Professor in Invertebrate Ecophysiology and Immune Function, added: “I think these findings raise the prospect that anthropogenic sounds in the marine environment are impacting marine invertebrate species in ways that have not been previously anticipated.”

The Leighton and Hauton study, using sound playbacks mimicking a ship at 100 yards and wind farm construction at 60 yards, found that both lobsters and clams changed their digging behaviors, and triggered changes in their overall activity level (lobsters increased, clams decreased); they found no marked effects on brittlestar activity.

Clearly, we are still in the early stages of understanding how our noises may be changing ocean ecosystems. In addition, the recent review paper affirms a longstanding concern that noise may act as a synergistic stressor, making animals more susceptible to other known stressors such as food shortages or rising ocean temperatures, noting that “Single stressors related to sound exposure may show no effects in isolation but when combined with other stressors effects may become pronounced.” New study designs are beginning to tease out these inter-relationships, giving researchers and ocean managers new tools that can move both science and policy forward in constructive ways.

The Arctic is one of the last expanses of the world ocean that has escaped the increasing din of shipping traffic over the past fifty years, but this respite may soon be ending. China and Russia are rapidly ramping up plans to take advantage of retreating sea ice along the northern coast of Siberia, opening up a new sea route from China to Europe that is significantly shorter than traveling through the Panama or Suez Canals. Meanwhile, the Canadian and Inuit governments have designated a large National Marine Conservation Area in Lancaster Sound, smack dab in the middle of the North-West Passage, which is similarly ripe for increased shipping in the coming decades.

The so-called Northern Sea Route (or Northeast Passage) will benefit from Russia’s fleet of forty icebreakers and eleven Arctic ports; by contrast, there are no Arctic ports on the US/Canadian coastline (one deep in Hudson Bay closed last year). Rob Heubert, a former member of Canada’s Polar Commission, notes that “The Chinese are taking the long view and they’re building ships, icebreakers, and ports to capitalize on the future, which may not be as far off as many think.” Maine Senator Angus King is championing an “Arctic” port in Portland, Maine to become the first US landing point for this increased Asian shipping traffic.

Some Russian observers suggest that the country’s investment in ports and icebreakers is a “money-losing… Soviet-style undertaking” that is bound to fail, with the port fees necessary to pay for this infrastructure likely to drive ships outside Russian territorial waters into the Transpolar Sea Route as that becomes accessible. Nonetheless, last week a Russian natural gas tanker made the fastest-ever transit of the Northern Sea Route, traveling for the first time without an ice breaker (the ship was designed to do some ice-breaking on its own).

Wherever and whenever Arctic sea lanes open up consistently enough to spur rapid increases in annual transits, it will be crucial to direct the traffic in ways that minimize the impact on relatively pristine arctic soundscapes. To this end, both the Canadian Coast Guard and the Pew Charitable Trusts have been working toward management of the North-West Passage; see this earlier AEI coverage.

The new Marine Conservation Area will preclude oil and gas development and seabed mining, but will not stop ship traffic. Lancaster Sound, now to be known by its Inuit name Tallurutiup Imanga, has been called the Serengeti of the Arctic thanks to its concentration of wildlife, especially narwhals, belugas, and polar bears. (Check out this image and video gallery!) In 2009, the Inuit sued the Canadian government to stop plans for seismic surveys in the area, beginning the process that culminated in the recent plan for joint management of these precious waters. Jackie Dawson, a University of Ottowa environmental geographer, is working with Inuit communities to identify ecologically and culturally significant areas, with hopes to designate “no go” and “go slow” zones to reduce sonic intrusions and the risk of ship strikes. This is exactly the kind of work we need to see across the polar regions, before the ice melts enough to change Arctic soundscapes forever.

Here’s an idea that’s so obvious that I’m amazed it isn’t at the center of public discussion about the declining orca population in and around Puget Sound. I happened upon it online (well, not exactly happened upon, thanks to my “whales noise” Google News section…); it was a guest commentary in a Vancouver Island paper, and I’ll let the author, Diane McNally, speak for herself:

Massive declines in salmon populations over the past 100 years have made it harder for the orcas to find food. Bodies of the males qualify as toxic waste, as they do not offload toxins in milk while nursing babies. Increasing ocean noise makes it harder for orcas to communicate with each other and to find food.

The remaining 78 southern residents are surrounded by buzzing boats any time they can be found. Can anyone say “watching” them during every daylight hour, as often as their location can be determined, for every day of their lives in the “whale watching season,” April to October, is helping them?

Put yourself in the orcas’ place. It’s as if you had neighbours who never turned off the leaf blower, lawn mower or loud music. Studies have shown behavioural changes in response to both noise and the presence of boats.

One next step in supporting the southern residents’ struggle to regain population viability is a retreat from entertaining ourselves by chasing and stressing individuals of this endangered population in the wild. We have the technology — underwater cameras and hydrophones — to see and hear them while allowing them the dignity of living their lives free from our desire to be entertained by them as they simply try to survive.

Indeed! Why should we humans have the “right” to hover around these wild creatures as they go about their days? Let an orca sighting become something rare and special: glimpsed from shore or happened upon while out on the water in your sailboat or on a ferry crossing.

Here’s a little taste of the life of an orca (if clicking the “play” arrow doesn’t start the audio after a few seconds, then click inside the white bars along the bottom and that’ll trigger it):

About 14 times a day, a large ship passes through Haro Strait on its way to or from the Port of Vancouver. From early August through early October, Port authorities are asking them to slow down, in a pilot project to assess how that might reduce the overall sound levels of shipping in this biologically important area. “I’d say it’s a first in the world, a project of this scale,” Orla Robinson, manager of the port’s Enhancing Cetacean Habitat and Observation (ECHO) program, said. “We’re trying to understand the relationship between slower vessel speeds, underwater noise levels and the effects on the whales.” In other locales, including San Francisco, ships are asked to reduce their speeds to reduce the chance of striking whales.

Haro Strait is a narrow passageway between Canada’s Vancouver Island the American San Juan Island, and is a prime summer feeding ground for the resident orca population, which has dwindled to less than 80 members. The voluntary speed restrictions will ask all ships to slow to 11 knots (about 13 mph) through a 16-mile corridor; cruise ships and container ships often run at 18-20 knots, while bulk carriers travel at 13-15 knots. The slowdown will reduce the noise of each ship as it passes by 40% or more, though it will linger in the area a bit longer; the net effect is expected to be beneficial by reducing the degree of impact on animals in the region.

“Underwater noise is one of the principal threats to southern-resident killer whales,” confirmedLance Barrett-Lennard, head of the Vancouver Aquarium’s cetacean research program. “The effect is thought to be most significant in years when chinook returns are poor, as predicted for 2017.” Marine researcher Rob Williams, co-founder of Oceans Initiative, added: “I’m extremely supportive of this effort. Slowing down is an inexpensive way to reduce noise levels quickly.”

Researchers will monitor noise levels and track how many ships heed the voluntary limit. They will also look at operational and financial impacts on the shipping industry, recognizing that there will be times when docking schedules or tide patterns may make it difficult for ships to slow down. If 50-70% of the ships moderate their speed, the project will be considered a success and will provide good data from which to consider further action in future years.

“If you’d asked me a year ago, there would have been some skepticism,” said Robert Lewis-Manning, president of the B.C. Chamber of Shipping. “As shipping companies have learned more about the ecological challenges, the more they have pitched in to participate. We’e seeing healthy support now. People are supportive of getting the data.” More than 30 companies so far have agreed to participate in the pilot program “where operationally and economically feasible, on a transit-by-transit basis,” including Holland America, Washington State Ferries, Westwood Shipping Lines, COSCO, and container shipping giant Maersk.

UPDATE, 8/7/17: As of today’s start of the research program, 54 companies have agreed to participate in the voluntary slow-down, including 100% of the members of three key trade associations, Chamber of Shipping, Cruise Line International Association Northwest and Canada and Shipping Federation of Canada. It appears that the vast majority of the expected 800 ship transits occurring during the study period will be adopting the slower speeds.

Turning science into policy is a long, slow road. The 2004 launch of the Acoustic Ecology Institute more or less coincided with the emergence of shipping noise as an environmental concern; symposia held by the National Marine Fisheries Service (now NOAA Fisheries) in 2004 and the Marine Mammal Commission in 2005 marked the start of growing scientific awareness that moderate chronic noise may be a bigger issue for marine life than the loud, transient sounds of sonar and airguns. AEI has focused on this key question from the start in specialreports and our ongoing news/science coverage.

In 2014, the International Maritime Organization (IMO) completed an at times sluggish six-year process and adopted voluntary noise reduction guidelines for large ships. Since then, the pace seems to be picking up as the shipping industry, port authorities, and eco-certification programs have all begun embracing the need to slow or reverse the long-term trends of increasing shipping noise in most of the world’s oceans.

This month, the port industry trade magazine Port Strategy included a long feature article that brings the story up to date. Among the new and encouraging developments is the work of Green Marine, a sustainability-certification outfit that works with 28 shipping companies and 38 ports in the US and Canada, including biggies like Seattle and New Orleans. After partnering with Transport Canada last year on a review of the current state of science in Understanding Anthropogenic Noise, Green Marine has now announced shipping-noise criteria that will be rolled out this year as a voluntary add-on for shipping companies that are part of their certification program, then will become a mandatory element of the Green Marine certification in 2018. The 5-stage criterion is modest to start, with increasing degrees of commitment (it’s unclear whether companies are expected to continually deepen their commitments, or not). The exciting news is that shipping companies are voluntarily committing to go beyond what’s required by current regulations; Green Marine Executive Director David Bolduc says:

“It is important to underline that the maritime companies and ports that are certified by Green Marine have voluntarily accepted to adopt the new underwater noise evaluation criteria with no regulations obliging them to do so. These participants made the commitment to address the issue more easily. For others, it was a relatively new issue; they needed to learn about noise, its sources, its potential impacts, and the mitigation measures.

“The indicator is a great tool to help them understand underwater noise and, most importantly, address this emerging issue. [It] is the result of collaboration among the industry, environmental organisations, the scientific community, and government representatives. Two intensive years of research and discussions were necessary to develop the five-level criteria.”

Meanwhile, following up on an AEI note from January, the Port of Vancouver’s inclusion of quiet ship guidelines as part of its reduced-fee Eco-Action initiative has generated its first takers: “We’ve heard anecdotally from some vessel sectors that they plan to upgrade their fleets to meet the new incentive standards,” says the port. “In the first quarter of 2017, two vessels have applied and been awarded a bronze level discount.”

And in the US, NOAA released an Ocean Noise Strategy Roadmap in late 2016 that will become the framework for ongoing research and management of ocean noise, including an emphasis on managing acoustic habitat. All this points to the next decade becoming a real turning point, as the past fifteen years of increasing awareness is channeled into constructive action to begin reducing our noise footprint in the seas.

A paper published earlier this year (on my birthday; what a nice present!) takes a close look at shipping noise levels along the Santa Barbara/Los Angeles coast, with particular attention to key habitat areas for several whale species. This region of offshore waters includes crucial feeding zones on the edge of the continental shelf, as well as the Channel Islands National Marine Sanctuary; meanwhile, some of the shipping traffic headed into the port of Long Beach (near LA) passes between the Sanctuary and the coastline.

The pictures generated by the authors surely qualify for the thousand-words designation, so I’ll let these key graphics tell most of the story—you can click any image to see a larger version. First up, here’s the number of ship transits occurring in these waters over five months (August to November 2009):

Next, here’s how the accumulated noise of all these ships translates into sound levels. The researchers modeled the sound levels at two different frequencies; this is because the 50Hz band is especially important to blue and fin whales, while the 100Hz band is most important to humpback whales. Note that at both frequencies, there are some areas that remain relatively protected from the worst of the shipping noise. Read the rest of this entry »

In yet another unforeseen consequence of global warming, scientists have begun charting the extent of a new underwater sound channel in the Beaufort Sea north of Alaska. As recently as the 1970’s, the water here was coldest just below the ice, but in recent decades two warmer layers have developed, one in the first 50 meters of water, and the second at around 200 meters deep. Since sound in water tends toward the coldest layers, it used to be dissipated by the rough bottom side of the ice, but now it’s reflected between the warm layers and travels much farther. Research in 2014 and 2016 documented sound transmission across 400 kilometers (250 miles), four times farther than before the emergence of this channel, dubbed the Beaufort Lens.

The near-surface has been warmed by an increased flow of meltwater from rivers and by larger ice-free areas exposed to the sun; this slightly warmer surface water has long been present in summer, but used to disappear in winter. Meanwhile, warmer waters entering the Beaufort from the North Pacific through the Bering Strait (and perhaps even from the Atlantic, through northern Canada) have contributed to the growth of the deeper warm layer. As is the case for most ocean noise research, the US Navy is a key funder; they’re interested in how increased noise transmission might “dramatically impact the effectiveness of sonar operations.”

The full extent of the Beaufort Lens sound channel is not yet known; further research is planned in the spring of 2018. The area affected is likely to vary with annual changes in the influx of warmer waters and to expand over time as longer-term climate change progresses. Increased shipping traffic is projected to be a major factor in rising ocean noise levels in the Arctic over the coming decades; oil and gas exploration could add to the din if the offshore oil industry rethinks its abandonment of these waters in recent years. In addition, general background noise in some areas could also increase thanks to longer-range transmission of whale calls, which have always been one of the primary sources of ambient sound in these waters.

This is great news, and we encourage other ports to follow in Vancouver’s enlightened footsteps. It is entirely possible to stop the steady increases in global shipping noise, and even to reverse these trends of the past few decades. Twenty years from now, our oceans can be quieter than they are today, and the isolated pockets still free of humanity’s noise footprints could expand, providing new hope for the world’s ocean creatures.

British Columbia has been a hotspot of concern—and research—about the extent and the impacts of shipping noise. The southern BC coast is close to acoustic saturation, with any increase in noise having the potential to completely overwhelm the underwater soundscape; meanwhile the northern coast holds a few areas that are still nearly free of human noise intrusion, and we need to do all we can to preserve these increasingly rare acoustic refuges. These contentious waters have been roiled in several contradictory though perhaps ultimately productive ways by recent Canadian government actions. In the month between Thanksgiving and Christmas, a northern pipeline was rejected and a southern one approved; meanwhile, ongoing research aims to identify the noisiest ships and help inform new regulations that could reduce overall noise levels.

The biggest headlines and fears have been spurred by the final approval of the Trans Mountain Pipeline expansion that will deliver oil from the Alberta tar sands to an existing port in Burnaby, BC. The port currently hosts about five tankers a month; the increased flow in the expanded pipeline (75% the capacity as the proposed Keystone XL) will necessitate about 35 ships a month, meaning an average of two tanker transits a day past Vancouver as they travel to and from the Strait of Georgia off the coast. These waters are currently burdened by shipping noise 85% of the time, and the increased traffic will push this to 100% in some areas. Concern centers on the tenuous status of the region’s orca populations, which are struggling to find the salmon they need; shipping noise makes it harder for them to track salmon with their echolocation clicks and to communicate with each other as they search for food. “Death by a thousand cuts, and this is a very deep cut,” says Deborah Giles, research director for the Center for Whale Research. “They’re spending more energy to find less food and we’re adding the equivalent of a rock concert,” she says. “These whales will not survive.”

Environmental groups will likely file suit challenging the approval, citing the government’s failure to mitigate the increased impact. At the same time, though, Fisheries Minister Dominic LeBlanc and Transport Minister Marc Garneau are working on a revamped recovery plan for the 80 remaining resident orcas. LeBlanc notes that Read the rest of this entry »

Some of the most interesting new work in ocean noise is revealing the myriad ways that humanity’s sounds can have negative impacts on ocean life other than marine mammals. Sure, everyone loves our warm-blooded kin, but there’s way more to the ocean ecosystem than dolphins, humpbacks, and seals. AEInews has been covering this leading edge for years (see these posts on shellfish larvae, crabs, and squid). Recently, at the triannual Effects of Noise on Aquatic Life conference, held this year in Dublin, a slew of new papers revealed further concerns.

This post from NRDC summarizes the highlights. One of the most striking findings was that 6 hours of shipping noise can damage the DNA in the cells of mussels, perhaps due to a stress response; similarly, protein structures in the sensory cells of cuttlefish were damaged by low-frequency noise. These would be some of the most profound impacts yet discovered; note, though, that the brief summary here does not specify the sound levels—some research on health effects use much higher exposures than are likely in the wild, as a way of identifying possible effects for further study at lower exposure levels. Other new studies followed on previous ones that suggest many animals respond to noise as if it were a predator; these responses often suggest increased stress, and are waste of precious energy, or disrupt feeding. Also of note is a one-off anecdotal observation (not yet studied systematically) of a hermit crab exiting its shell after exposure to low-freqency sound; it appeared to be examining its shell, perhaps trying to determine the source of the disruption, or checking for physical damage. While out of its shell, it would be vulnerable to predation.

All this new research is both exciting, as it reveals the vast and subtle role of sound in the natural world, and sobering in facing us with the widespread consequences of our heedless sonic intrusions into wild ecosystems.

Ship traffic through Canada’s Northwest Passage has more than doubled since 2004 and tripled since the 1980s, mostly thanks to much longer open-water seasons as the Arctic continues to warm. Today’s 300-350 voyages per year is expected to double again as both mining and tourism rise in the years ahead.

In response, there are increasing calls to manage the increased ship traffic, both to improve safety and minimize environmental impacts. A new report from Pew Charitable Trusts draws on recent data, previous Canadian government reports, and First Nations concerns to make the case. “Corridors give people a roadmap to follow,” said Louie Porta, one of the report’s authors. “A robust corridor system is a recommendation for vessels to stick to a very, very small portion of the Arctic waters as opposed to now, where there are no limits – vessels can basically go wherever they want.” The map below shows 2014 ship tracks criss-crossing key biologically important areas in the western part of the Northwest Passage; here’s a link to the full map.

Government and Inuit groups have identified at least 38 areas of ecological and biological significance (EBSAs) occupying nearly 50 percent of Canadian Arctic waters. “There’s a high concurrence of vessel traffic patterns and areas of biological significance. We can’t say that ships can’t go where the environment is significant, but it’s possible to create a more flexible, dynamic policy that identifies what times of year ships can be in certain locations,” said Porta. . . . Under the proposed framework, shipping corridors would be identified by integrating human and vessel safety, environmental protection and Inuit rights.

The Canadian Coastguard has been working on a similar plan to concentrate shipping traffic. However, their current proposal for the Beaufort Sea allows shipping in 45% of regional ecological, biological and Inuit areas of significance, while the Pew report’s recommended lanes overlap just 25% of these key areas.

Arctic shipping is a much bigger issue than just the Northwest Passage. Arctic Deeply has been quick to dive into this important topic, including a recent piece on the impact of Arctic shipping noise on whales, and a long Q&A with a geographer who focuses on climate change and the Arctic.

The British Columbia coast is a wild territory, yet one pockmarked with major shipping facilities. Four related ports stretch down the coast from Prince Rupert, sending coal, grain, and other products to Asian markets and south to the U.S. and beyond. Canadian First Nations and environmental groups have been raising alarms about the cumulative impacts of increased development in this remote area, while innovative ocean noise research is modeling the ways different species’ listening and communication ranges may be affected by more shipping.

Now, plans for two more port facilities, on islands just down the coast from the current Prince Rupert complex, have perhaps gone too far. These are natural gas facilities, next to and literally on top of the Flora Bank, a primary feeding area for juvenile salmon. Project proponents stress that their design will avoid damaging the area, but they seem to be discounting the potentially devastating acoustic impact of the bringing huge ships this close to a sensitive habitat.

Flora Bank, in intertidal waters off Lelu Island, contains about 60 per cent of the eel grass habitat in the Skeena Estuary, a watershed that gives birth to 200 million young salmon each year. This expanse of eel grass is a crucial way station for those that exit out the northern branch of the Skeena (the waterway off the right side of the image above); studies indicate 2-8x more salmon enter the ocean here than in other areas to the south; by some accounts, 90% of the Skeena salmon run comes through here. “It is absolutely clear that Lelu Island is the worst location for such a facility,” says Dimitry Lisitsyn, a Russian biologist who has seen the effects of oil and gas development in his country.

The companies behind the projects are making efforts to minimize disturbance of the seabed by building a raised pier, jetty, and suspension bridge and will fund the establishment of new seagrass beds nearby, with a goal of doubling the number of young salmon being supported—though similar habitat-creation projects have a spotty success rate. Yet even if they do keep a light physical footprint and avoid creating new sediments that would damage the eelgrass beds, the ships coming into both of the new ports will change the acoustic habitat irrevocably.

Alexander Vedenev, head of the Ocean Noise Laboratory at the Russian Academy of Sciences, says that noise levels from the plant and ships will be audible to young salmon out to about 3km away; some young fish will avoid such sound levels or be startled away with the approach of a ship, while those who linger are likely to experience higher than normal stress levels. Both stress and reduced feeding time can affect long-term survival rates; the worst-case scenario is an abandonment of this crucial feeding ground. The current Ridley Terminals—and shipping lanes serving the other Prince Rupert ports—are just beyond the 3km range, while the new Prince Rupert LNG facility will be 2km from the edge of the Bank, and the Pacific Northwest LNG facility is right on its edge, thus flooding the entire Bank with noise.

So here we have a stretch of wild and beautiful coast, already burdened by significant shipping noise and facing the prospect of many other proposed ports, including a big one at Kitimat, in the lower right of the above image. Now, they want to extend the already-developed stretch of coastline right down to the very edge of an established critical habitat for salmon, building a jetty over the eelgrass itself and dredging a pier area off its outer fringes. This is indeed adding clear injury to an already-existing insult of prime oceanic habitat where the bulk of the Skeena’s salmon travel to and from the sea. How much is enough, folks? Yes, yes, I suppose we could just consider that stretch of coast south of Prince Rupert to be a sacrifice zone; why not extend it right to the lip of the estuary? And I don’t know the area well enough to say with certainty that the salmon can’t find other areas to feed as they make their initial foray from the inland waters of their birth and out into the wild unknown of the seas….but I can easily look at that map above and appreciate the incredible beauty of such a big, wild river, pouring through the mountains from headwaters deep in the heart of British Columbia. Why would we want to desecrate its mouth?

Agencies, researchers, and NGOs are all concerned about the effects of chronic moderate noise on whales, seals, and fish (along with crustaceans and even eggs and larvae). NOAA’s ocean noise mapping project is a big step forward, but it’s largely based on modeling of known ship and seismic survey activity. Actual recordings made at sea by various researchers serve as “ground-truthing” for these models; early indications have been that the models are pretty good, usually within 5-10dB of actual recorded levels.

The ONRS network takes acoustic monitoring another step forward by deploying identical equipment in many regions, thus collecting “consistent and comparable multi-year acoustic data sets covering all major regions of the U.S.” In addition to getting a better idea of regional differences (and consistencies), researchers will be investigating “how the ‘soundscapes’ at each of these sites changes, i.e. does it become noisier, are there more or less biological sounds, and is there a dramatic shift in the species present?” All this will feed into NOAA’s ten-year effort to develop an Ocean Noise Strategy.

The most recent deployment took place this fall at the Cordell Bank National Marine Sanctuary off the coast near San Francisco (it’s not even on the maps on the NOAA site yet, though I added it above as NRS11). The hydrophone deployment mission (right) received substantial funding from the International Fund for Animal Welfare (IFAW), along with the ongoing NOAA support for data collection and analysis. Cordell Bank is one of the richest foraging grounds for marine mammals, thanks to an upwelling of cold water that attracts a wide range of species to feed. At the same time, many of the thousands of ships traveling from Asia to ports in San Francisco Bay and further south along the California coast pass close enough that their “acoustic footprint” extends into the Sanctuary. This can, at the very least, make it harder for whales or fish to hear each other as well as they’re used to, limiting the area over which they can communicate and causing them to raise their voices. There are also indication that some species expend energy avoiding moderate noise, and that feeding and perhaps mating can be temporarily disrupted. Most pernicious may be the possibility that living in elevated noise can increase physiological stress, triggering “a suite of negative effects,” according to one of the researchers.

Other research efforts are also adding to our understanding of the effects of shipping noise. In Canada, Port Metro Vancouver recently deployed a hydrophone to examine the underwater noise from container ships headed into its facilities. 3000 such vessels traverse the waters each year, along with even more ferry transits and various recreational boats. It’s part of the Port’s Enhancing Cetacean Habitat and Observation Program. One of its most interesting goals is to zero in on ships that may be unusually loud and in need of some maintenance:

The hope is to establish baseline information to track noise levels and to identify noise levels from specific ships. The results could lead to simple mitigation measures such as hull and propeller cleaning, shore-based financial incentives, and information for regulatory agencies and for naval architects to build quieter ships.

And in the Bering Sea, acoustic monitoring is providing important baseline data on marine mammal presence, which will play into any future oil and gas development, as well as the potential for global shipping to extend into Arctic regions as polar ice melts:

“This passive acoustic monitoring technique allows us to detect the presence of vocalizing marine mammals continuously — 24 hours per day — in all weather conditions, over periods of weeks to months, over distances of 20 to 30 kilometers, and is a proven sampling method in the waters offshore Alaska,” explained lead researcher Kathleen Stafford.

We’re listening more closely and widely than we ever have—the next question will be, are we willing to actually do something with what we learn, and find ways to slow or roll back our relentless intrusion into the natural soundscapes of the oceans?

Over the past decade or so, concern about ocean noise has expanded from its initial focus injuries and deaths caused by periodic loud events, such as sonar or seismic surveys. Many researchers are now working to understand the ways that widespread, chronic shipping noise affects marine creatures’ behavior, foraging success, and stress levels. Long-term deployment of hydrophones, sound models that extrapolate from shipping data, and slow-but-steady improvements in our knowledge of the hearing ranges and population densities of particular species have all combined to open exciting new avenues for research that can inform policy decisions in the years to come.

Using these new measurement and modeling techniques, researchers can quantify the “acoustic quality” of marine habitats. This starts with charting the extent of shipping noise, while also considering the different auditory ranges of various species of interest. Next, researchers map where animals tends to congregate in various seasons, to identify areas that are especially important to each species.

Of particular importance is identifying areas that have, so far, remained relatively free of shipping noise. If at all possible, we’ll want to avoid extending the human noise footprint into these increasingly rare acoustic havens. A research team that’s been active on Canada’s southwest coast over the past few years has been at the forefront of these techniques, and has just published a new paper that introduces the concept of “opportunity sites”—areas used by each species that are still relatively quiet, and so have high long-term conservation value.

“We tend to focus on problems in conservation biology. This was a fun study to work on, because we looked for opportunities to protect species by working with existing patterns in noise and animal distribution, and found that British Colombia offers many important habitat for whales that are still quiet,” said Dr. Rob Williams, lead author of the study. “If we think of quiet, wild oceans as a natural resource, we are lucky that Canada is blessed with globally rare pockets of acoustic wilderness. It makes sense to talk about protecting acoustic sanctuaries before we lose them.”

These new opportunity maps make it painfully obvious how little of each species’ habitat is free of excessive shipping noise. In the example above, harbor porpoises can only find high quality acoustic habitat in a couple of small areas. Without some concerted effort to protect these areas, they will continue to shrink.

While recognizing that many areas of critical habitat are already too loud (in particular, the entire Seattle/Vancouver region), the authors acknowledge that reducing existing noise is difficult—limiting shipping, or reducing the noise made by boats, has social and economic costs that can be hard to accept. By contrast, the areas they’ve identified merely need to be maintained in close to their current acoustic condition, which will be far easier to accomplish. As the authors note:

In our professional opinion, if two places are equally important to whales, with one being noisy and the other being quiet, it would be helpful to identify those areas and present that information to decision-makers. The noisy area may require mitigation, whereas the quiet area may make a more attractive or convenient candidate for critical habitat protection, either because it represents higher quality habitat to the animals or because it imposes lower economic costs to society to mitigate anthropogenic threats.

This may not mean excluding new activities from these regions, because, again in the authors’ words, “a particular marine environment could be dominated by anthropogenic underwater noise that is perceived as being loud to one species, but quiet to another.” Indeed, the opportunity maps differ for each species (though that area on the eastern side of the large island of Haida Gwaii recurs in most). So, we will need to pay close attention to what species are present, how well they’ll hear the new noise sources, and the ways they may respond.

Generally, large ship noise is far more audible for baleen whales (humpback, fin, etc.) than for smaller toothed whales (dolphins, orca), which vocalize and hear at higher frequencies. That’s not to say that the smaller whales don’t hear big ships; they often do, and in many cases, they respond at a lower sound level than larger whales, so even if the ships are “fainter” to their ears, their reactions may be similar.

While this paper steers clear of any sort of advocacy tone, and does no more than present the new “opportunity sites” analysis and mapping technique, the waters being studied are at the center of a contentious public policy debate. The proposed Northern Gateway pipeline from the oil sands region of Alberta would dramatically increase tanker traffic to the existing deep-water port at Kitimat (yellow arrow, left). Such an increase through Caamano Sound (red arrow, left) would threaten the humpback whale opportunity site (map, left) identified just south of the Sound. Several years ago, co-author Rob Williams told reporters, “Caamano Sound may be one of the last chances we have on this coastline to protect an acoustically quiet sanctuary for whales. … We don’t exactly know why this area is so rich, but there are some long, narrow channels that serve as bottlenecks for food, making it easier for whales to feed.” A consortium of environmental organizations is currently challenging the Canadian government’s approval of the pipeline, claiming that the approval did not take into account the humpback recovery plan, identifying Hecate Strait (the larger area between the mainland and the large offshore island) as a critical humpback feeding ground. The pipeline is being challenged on several fronts (including strong opposition from B.C. First Nations communities); considering acoustic habitat protection, limiting new ship traffic during the times of year when the current opportunity sites are being heavily used would seem to be the least we can do.

Bioacousticians and marine advocates have been closely following plans for the Northern Gateway pipeline in British Columbia, which would greatly increase ship traffic in some coastal waterways that are relatively quiet so far; see previous AEInews coverage. But another pipeline project, farther along in the permitting process, could push the already stressed waters of southern BC and northern Washington to the acoustic breaking point. The Trans Mountain Pipeline, built in 1953 and expanded several times since then, is gearing up to nearly triple its capacity and make adaptations that will allow heavy tar sands oil to be moved to the Pacific coast for shipment to Asia.

The expanded Trans Mountain Pipeline would have 75% of the capacity of the proposed Keystone KL pipeline to the Gulf of Mexico, so it has triggered active resistance on similar climate change grounds as Keystone. At the same time, ocean advocates are stressing the cumulative impact of the additional 720 tanker transits that would occur in already-busy waters that include critical habitats for killer whales, sea lions, and other species. At this point, most of the additional capacity is targeted for Burnaby, BC (increasing monthly tanker arrivals from 5 to 34), though the pipeline also serves terminals in northern Washington state. (Some of the current capacity is refined and used in North America, but virtually all of the increased capacity will be shipped overseas; thus the tanker traffic will increase 7-fold despite the smaller capacity increase.)

The Canadian Department of Fisheries and Oceans has just released a review of the Trans Mountain proposal, which is currently being considered by the National Energy Board (NEB), and finds it lacking, saying it contains “insufficient information” to adequately assess the threats posed both by underwater noise and ship strikes. “The assessment considers noise from a single project-related ship, without taking into account the additive and cumulative effects of existing noise,” Fisheries and Oceans Canada concludes.

Marine advocates second that concern. Margot Venton, a staff lawyer with Ecojustice, stresses that “The critical habitat is basically as noisy as it can be. We need to make it quieter.” Misty MacDuffee, a fisheries ecologist with Raincoast Conservation Foundation, said anything that impedes the ability of whales to feed is a serious concern. “It’s just the growing din,” she said. “They are trying to [communicate and hunt] in an increasingly loud environment.” (Thanks to the Globe and Mail for their coverage and all these quotes.)

The NEB review is slated to be concluded by July; the federal government will then take six months to consider the NEB’s recommendation and make a final decision. If approved, construction could begin in 2016 and be completed the following year.

UPDATE, 7/14/16: The NEB has recommended that the pipeline be approved, despite the likelihood that additional ship traffic will saturate the acoustic environment to the point that ship noise is present in some areas nearly 100% of the time (currently 85%). Transmountain will need to meet 157 conditions, but they’re confident that will be achievable. The final stage of the approval process is a final decision from the Canadian government, which is expected by the end of this year.

PacificWild, a British Columbian environmental organization, has deployed a network of 6 hydrophones in waters along the northern coast of that province. This region of offshore islands and dramatic forested fjords is relatively wild, and quiet, especially as compared to the shipping-intensive region in southern BC around Vancouver Island and nearby Puget Sound in Washington State. But development proposals (including tar sands and other oil and gas ports) may mean up to 3000 supertankers per year will pass through these northern waters, bringing an expansion of the acoustic smog that already blankets most of the world’s oceans.

Ian McAllister of Pacific Wild stresses that “Most of the species that are acoustically sensitive rely on a quiet ocean in order to communicate, in order to forage, in order to survive here,” and notes that the hydrophone array will gather crucial baseline acoustic data that can help inform management decisions to be made in the next few years.

A proposal to exclude whale-watching boats from nearshore waters off San Juan Island in Puget Sound has been revived by a local orca protection group, Orca Relief Citizens Alliance. A similar plan was proposed by NOAA in 2009-11, but was abandoned after push-back from whale-watching groups, with a speed limit introduced instead. In recent years, the population of resident orcas has fallen to a 30-year low, and is down to 77 after 4 deaths during 2014, including the first new calf to be born in two years.

“This is only an immediate solution to a dire situation,” said Orca Relief Executive Director Bruce Stedman. “When salmon levels are so low, the whales are very stressed when searching for food. Pursuit from whale watching boats causes more stress.”

However, the proposed “no-go” zone contains just 0.5% of the resident orcas’ federally designated critical habitat and is heavily used by orcas for just a few weeks a year, so the idea been criticized by both whale watching groups and some orca advocates, including Ken Balcomb of the Center for Whale Research. “The no-go zone is an absurd waste of concern and a futile effort legally,” Balcomb said. “The whales will go where the chinook salmon are in abundance, and it is these fish that should receive our concern.”

It used to be that most concern about human noise and ocean life was centered on whales and the two loudest sound sources: sonar and seismic surveys. But in recent years, we’ve seen a growing wave of studies looking at how chronic, moderate ship noise can interfere with normal behavior and development of other creatures, including squid, fish, crustaceans, and other “lower” species. Four recent studies add to the list of known or suspected ways that shipping and recreational boat noise may be wreaking previously unsuspected havoc throughout the oceanic web of life.

The most dramatic results came in a study of eels’ responses to predators (above). When exposed to ship noise, only half as many eels responded to an ambush attack from a predator (just 38% reacted, down from 80%); and, those that did react did so 25% slower than normal. Likewise, researchers tested eels’ ability to detect a “pursuit” predator that follows the eels before attacking; in this case, the eels in ship noise were caught twice as quickly. Looking deeper, the researchers examined how noise affects metabolic rates, stress, and breathing rates, and an interesting feature of eel life, the preference for using one side of their body when interacting with other eels and when hunting. The researchers explain:

“In the same way we write using our right or left hands, fish have a preferred side to approach a predator or to stay next to shoal mates with. We watched each eel as it explored a maze in ambient conditions to classify its right or left bias, then we exposed half to ship noise and half to more ambient noise. Their preferences went away when they were exposed,” says Dr Steve Simpson of the University of Exeter, lead researcher on the study. The team suspect this means ship noise affects eels’ cognitive processes, which could mean other processes, like learning, may also be affected. Alongside raised metabolic and ventilation rates, the scientists note the stress being caused by the shipping noise is similar to the levels fish exhibit in ocean acidification studies.

“We know shipping isn’t going to stop, but we can do things like move a shipping lane so it doesn’t interact with the migrations paths of animals,” Simpson suggests. “It’s a pollutant we have more control over than something like atmospheric carbon dioxide. These animals are having to deal with all the stressors globally, so if we can alleviate just one it might give the animals more resilience to other stressors like ocean acidification, which will come later.”

A study of two species of small fish highlights species differences and the ways that noise can alter behavior in unexpected ways. Here, one species of fish exposed to ship noise actually responded more quickly to the presence of a predator,

For several years, AEI has been excited about the ever-expanding networks of ocean observatories coming online around the world. A recent article on LiveScience detailed some of the benefits of the arrays of research stations deployed offshore by Ocean Network Canada, which collect all manner of data: physical, chemical, biological, geological, and acoustic. Their two networks, the offshore NEPTUNE (left below) and the near-shore VENUS (right below), consist of permanent installations on the floor (“nodes,” shown as orange squares below) as well as mobile moored sensors that may take measurements higher in the water column (yellow dots). A similar US network, dubbed Regional Scale Nodes, is being planned off the coast of Washington and Oregon.

While the observatories are enabling in-depth study of complex process in ways not previously possible(click that link for a glimpse of the amazing topics being explored…yes, do it!), the audio feeds coming from some of the nodes hold special excitement for many researchers. “If you want to study what’s going on in the ocean, the best tool by far is sound,” said Tom Dakin, an acoustic specialist at ONC’s sensors technology development office.”There are all kinds of sounds being made in the ocean, and they all have a telltale signature. . . . If you start putting in a bunch of external man-made noise, [whales] are going to have a hard time communicating,” Dakin said. It’s like trying to have a conversation with somebody at a rock concert — you have to shout, you can’t hold a conversation for very long and you wouldn’t be able to detect different inflections that you would normally be able to hear. He has been diving when a big ship has gone by, and “it feels like somebody’s whacking you in the chest with a two-by-four,” he said.

But while scientists are keen to hear what the new undersea recordings have to tell us, the US and Canadian Navies are far less enthusiastic. They’re concerned that the audio feeds, which are freely available to scientists and the public as downloads and via live online feeds, will reveal sensitive information about submarine and ship movements, navy training activities, and even the sound signatures of individual vessels. The two navies have arranged with researchers to have an audio bypass switch that allows them to divert the audio streams into a secured military computer—sitting in a locked cage at the research facility where the data comes ashore—at times when their ships are nearby (and also at some random other times, so that their diversions don’t give away any secrets on their own!). This article from The Atlantic dug into the way this system works, along with a quick look at naval concerns about sound from as far back as 1918. The data diversions from Ocean Networks Canada’s system (often triggered by the US Navy) occur several times a month and last from hours to days. As noted by The Atlantic:

While the Canadian military has yet to return a request for comment, the U.S. Navy reminds me that naval ship movements are classified information, and the fact that those movements might potentially be broadcast on the internet is obviously of concern. “The value of having a cabled system is that it releases data live to the internet,” says U.S. Navy oceanographer Wayne Estabrooks. “But there are some times where we want to protect information, so we have to do diversions.”

…

“There’s a long tradition of the ocean being the exclusive domain of the militaries and the fishing community, and we’re more or less interlopers in this world,” says [Kim] Juniper, the microbiologist who showed me the photo of the computer in the cage. “The world is changing. . . It’s going to come to a point in the future where this is no longer going to be feasible for the navies to put resources into sorting all this data,” he later says. The hydrophones alone generate 200 gigabytes of raw data each day, and there are other, similar networks of Internet-connected sensors that already exist, or are soon to come online.

Dakin notes, though, that only 4% of the data is lost, and is returned to the science pipeline, often immediately and nearly always within a week. The military filters out their ship noise, but leaves the rest of the data intact (at least, whatever data is not also in the frequency range of the navy ships or other sensitive sonic activities). “At end of the day, we hardly miss any data at all,” he says. You can listen to live streams of ONC acoustic data here, and, since that’s rarely very exciting, to a collection of highlights of images and sounds here.

The International Maritime Organization (IMO) has adopted the first-ever comprehensive guidelines on shipping noise. The voluntary guidelines mark the first step toward a longer-term goal of bringing noise factors into planning for both ship design and shipping routes.

This marks the successful completion of a six-year process, largely spearheaded by NOAA, the US Coast Guard, and their German counterparts at IMO. The US Chamber of Shipping, a trade organization, has also been engaged from the start. While the guidelines are voluntary, leading some observers to question their value, it is expected that many key players will begin to work with the guidelines in coming years. In general, the shipping industry is far more willing to design new ships to be quieter, than to retrofit older ships. Ed. note: one fascinating insight from the early IMO process was that global shipping noise may be dominated by relatively few unusually loud ships in each size class.

In this ocean noise map created by NOAA, the darkest areas represent noise about 60dB above natural ambient levels

provide guidance for designing quieter ships and for reducing noise from existing ships, especially by minimizing the roar produced by ship propellers, in a process known as cavitation; and

advise owners and operators on how to minimize noise through ship operations and maintenance, such as by polishing ship propellers to remove fouling and surface roughness.

UPDATE, 6/4/14: In 2012, the International Organization for Standardization (ISO) developed formal standards for the measurement of underwater sound from ships. ISO standards provide detailed specifications that assure consistency in what is being measured (frequencies, reporting metrics), and how (distance from sound source, conditions, etc.). Combined with the IMO guidelines, shipping companies now have the tools they need to provide clear information on the noise footprint of their vessels and the design choices they make to reduce noise; although neither the IMO nor ISO specify specific limits or targets for ship noise, they provide standardized ways of reporting on the noise of ships. RINA Services, which provides a wide range of independent marine certifications, has just added a new voluntary notation, DOLPHIN, that combines the IMO and ISO reporting standards, and gives shipowners a third-party certification option to specify commercial vessels which have implemented solutions to minimize radiated underwater noise.

Two new research projects are taking important next steps in understanding the importance of sound, and clear listening, to whales. In recent years, ocean bioacousticians have introduced the concept of “communication space” or “effective listening area” to scientific parlance. This began as a conceptual framework for thinking about how human sounds (especially shipping noise) may reduce the area across which whales can hear and be heard; researchers are now digging into more of the details of how this may actually impact animals in their daily lives. After severalrecentstudies that focused on whales hearing each other (and so framing their results in terms of “communication space”), two new studies are gathering initial data that may inform considerations of the ways whales listen for the presence of prey. While whales can, and do, change some of their communication signals or patterns in order to be better heard by other whales in noisy conditions, there’s no such compensation that can help a whale hear their prey through a wash of noise.

Both of the new studies are taking advantage of acoustic tags to allow scientists to listen in on whales as they are foraging. These tags are about the size of a large cell phone, and are attached to the animals with suction cups; they remain attached for up to 16 hours, then float to the surface for retrieval. While attached, they record all sounds the whales hear and make, as well as logging swimming speed and dive orientation.

One study is further along, having just published its first results, which confirm that orcas can hunt in near-total darkness, apparently relying only on zeroing in on their prey (in this case, seals) by listening for their mating calls. These orcas do not use echolocation while hunting (other orcas, hunting salmon, do echolocate); they hunt in stealth mode, then dispatch their victims with a swat of their tail flukes. This initial evidence is not totally conclusive; followup studies will confirm that orcas do, indeed, seek out seal sounds. And, this sort of study is but the first step toward quantifying the extent to which ocean noise may limit the range over which orcas can hear seals while hunting.

The second study will begin next year, and will be putting the acoustic tags on large whales, to see whether they’re using acoustic cues to help locate aggregations of fish. According to Dr. Rochelle Constantine:

“Acoustics within the marine space are really important for many organisms, yet we don’t know a lot about how it drives organisms’ interaction with their environment. We’re interested in looking at how the larger animals use the acoustic environment, particularly for food, and testing the hypothesis that food patches have specific sound signatures.”

She said the sound of “bait balls” of prey, such as schools of fish, could be greatly heightened when a feeding frenzy involving larger fish and seabirds broke out. Dr Constantine said whales had been observed swimming rapidly from over a kilometre away toward prey aggregations, “so we’re very interested to find out if there are specific acoustic cues they home in on”.

This study plans to play recorded sounds of fish aggregations and other prey sounds while the tags on the whales. (I suppose if they happen to get lucky and have an actual feeding event occur while tags are attached, that will be a bonus, but the playback will serve as a reliable testing condition.) This team is also interested in using acoustic tags on large fish and sharks, to explore the ways they may rely on listening, as well.

Innovative research along the coast of British Columbia has quantified the degree to which shipping noise is reducing the distance at which whale vocalizations can be heard. This is one of the first studies to use recordings of actual ocean noise levels to examine how the “communication space” of whales is affected by shipping noise in an area where whale conservation is a priority. Among its troubling findings is that endangered orcas are facing the highest levels of noise in areas that are legally designated as critical habitat, with communication space reduced to 25% or less even in average noise conditions; over the entire study region, the area over which orcas can hear each other can be reduced by 62% during average noisy conditions, and 97% during the noisiest times. Humpback whales face nearly as large reductions in some key areas (though not formally designated critical habitat; and, notably, are showing signs of a tenuous recovery in some of the areas studied), while fin whales, who have louder calls than the other species, are only mildly affected by shipping noise.

(noise levels and communication space in median noise conditions)

Communication space (alternatively termed “effective listening area”) is a relatively recent introduction into scientific parlance; it’s a measure of the area within which a particular species can hear and be heard by others of its kind; both marine and terrestrial bioacousticians have begun using this framework to better understand the ways animals may be affected by increased background noise introduced by human activities, including shipping, roads, and airplane overflights. Previously, small increases in background noise were commonly considered to cause only negligible impacts, since there is rarely a clear or consistent behavioral reaction. However, many animals rely on hearing things at the edges of audibility (calls of their kin, the approach of predators, the presence of prey), and a significant reduction in an animal’s communication space can cause a need to use more energy hunting, or to be in a heightened state of alertness (and stress) to avoid predation.

After a couple of years with no progress to report, the International Maritime Organization (IMO) appears to be nearing completion of “Voluntary Guidelines for the Reduction of Underwater Noise from Commercial Shipping.” This process began in 2008 with a burst of activity and focus from the US and European IMO representatives, but appeared to languish in recent years (see this earlier AEInews report, with links to key documents).

The effort falls under the purview of the IMO’s Marine Environmental Protection Committee (MEPC), which assigned development of the standards to its sub-committee on Ship Design and Environment (DE). The DE formed a “drafting group” led by the US, and this group has nearly completed its work, with just one paragraph in the preamble still to be solidified. At its March 2013 meeting, the DE subcommittee approved the draft guidelines; their next step along the long and winding bureaucratic road will be their submission to the full MEPC at its next meeting, in April 2014.

The draft guidelines are currently not publicly available, but the DE meeting summary notes:

The non-mandatory Guidelines are intended to provide general advice about reduction of underwater noise to designers, shipbuilders and ship operators and consider common technologies and measures that may be relevant for most sectors of the commercial shipping industry. Designers, shipbuilders, and ship operators are encouraged to also consider technologies and operational measures not included in these Guidelines, which may be more appropriate for specific applications.

The guidelines give recommendations on predicting underwater noise levels, such as using underwater noise computational models; standards and references that may be used, including ISO/PAS 17208-1 “Acoustics – Quantities and procedures for description and measurement of underwater sound from ships – Part 1: General requirements for measurements in deep water” (see this ISO press release on these new standards); design considerations; onboard machinery selection and location; additional technologies for existing ships; and operational and maintenance considerations.

Here’s hoping that the MEPC is able to take up the Guidelines at their 2014 meeting as planned, completing this modest first step of encouraging the shipping industry to incorporate noise emissions into the design of new vessels. The ISO/PAS standards will provide clear guidance for measuring the noise footprint of ships, though the IMO is not ready to suggest or mandate any particular maximum noise levels at this time. See this AEInews post on NOAA’s recent ocean noise mapping project; shipping noise is the predominant human contributor to overall ocean noise levels.